xM: generate and use a bundle icon

xM/CMakeLists.txt

@@ -25,8 +25,21 @@ add_custom_command (OUTPUT xC-proto.swift
 	COMMENT "Generating xC relay protocol code" VERBATIM)
 
 set (MACOSX_BUNDLE_GUI_IDENTIFIER name.janouch.${PROJECT_NAME})
+set (MACOSX_BUNDLE_ICON_FILE xM.icns)
+
+# Avoid including binary files in the repository by generating icons in code.
+# sips(1) + Javascript + iconutil(1) could probably also be used.
+find_program (SWIFT_EXECUTABLE swift REQUIRED)
+
+set (icon "${PROJECT_BINARY_DIR}/${MACOSX_BUNDLE_ICON_FILE}")
+add_custom_command (OUTPUT "${icon}"
+	COMMAND ${SWIFT_EXECUTABLE} "${PROJECT_SOURCE_DIR}/gen-icon.swift" "${icon}"
+	DEPENDS gen-icon.swift
+	COMMENT "Generating xM application icon" VERBATIM)
+set_source_files_properties ("${icon}" PROPERTIES
+	MACOSX_PACKAGE_LOCATION Resources)
 
 # Other requirements: macOS 10.14 for Network, and macOS 11 for Logger.
 set (CMAKE_Swift_LANGUAGE_VERSION 5)
 add_executable (xM MACOSX_BUNDLE
-	main.swift ${PROJECT_BINARY_DIR}/xC-proto.swift)
+	main.swift "${icon}" "${PROJECT_BINARY_DIR}/xC-proto.swift")

xM/gen-icon.swift

@@ -0,0 +1,104 @@
+// gen-icon.awk: generate a program icon for xM in the Apple icon format
+//
+// Copyright (c) 2023, Přemysl Eric Janouch <p@janouch.name>
+// SPDX-License-Identifier: 0BSD
+//
+// NSGraphicsContext mostly just weirdly wraps over Quartz,
+// so we do it all in Quartz directly.
+import CoreGraphics
+import Foundation
+import ImageIO
+import UniformTypeIdentifiers
+
+// XXX: Not even AppKit provides real superelliptic squircles; screw it.
+func drawSquircle(context: CGContext, bounds: CGRect, radius: CGFloat) {
+	context.move(to: CGPointMake(bounds.minX, bounds.maxY - radius))
+	context.addArc(
+		center: CGPointMake(bounds.minX + radius, bounds.maxY - radius),
+		radius: radius, startAngle: .pi, endAngle: .pi / 2, clockwise: true)
+	context.addLine(to: CGPointMake(bounds.maxX - radius, bounds.maxY))
+	context.addArc(
+		center: CGPointMake(bounds.maxX - radius, bounds.maxY - radius),
+		radius: radius, startAngle: .pi / 2, endAngle: 0, clockwise: true)
+	context.addLine(to: CGPointMake(bounds.maxX, bounds.maxY - radius))
+	context.addArc(
+		center: CGPointMake(bounds.maxX - radius, bounds.minY + radius),
+		radius: radius, startAngle: 0, endAngle: .pi / -2, clockwise: true)
+	context.addLine(to: CGPointMake(bounds.minX + radius, bounds.minY))
+	context.addArc(
+		center: CGPointMake(bounds.minX + radius, bounds.minY + radius),
+		radius: radius, startAngle: .pi / -2, endAngle: .pi, clockwise: true)
+	context.closePath()
+}
+
+func drawIcon(scale: CGFloat) -> CGImage? {
+	let size = CGSizeMake(1024, 1024)
+
+	let colorspace = CGColorSpaceCreateDeviceRGB()
+	let context = CGContext(data: nil,
+		width: Int(size.width * scale), height: Int(size.height * scale),
+		bitsPerComponent: 8, bytesPerRow: 0, space: colorspace,
+		bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue)!
+	context.scaleBy(x: scale, y: scale)
+
+	let bounds = CGRectMake(100, 100, size.width - 200, size.height - 200)
+	// The radius was something like size.{width,height}/6.4, at least for iOS.
+	drawSquircle(context: context, bounds: bounds, radius: 180)
+	let squircle = context.path!
+
+	// Gradients don't draw shadows, so draw it separately.
+	context.saveGState()
+	context.setShadow(offset: CGSizeMake(0, -12).applying(context.ctm),
+		blur: 28 * scale, color: CGColor(gray: 0, alpha: 0.5))
+	context.setFillColor(CGColor(red: 1, green: 0x55p-8, blue: 0, alpha: 1))
+	context.fillPath()
+	context.restoreGState()
+
+	context.saveGState()
+	context.addPath(squircle)
+	context.clip()
+	context.drawLinearGradient(
+		CGGradient(colorsSpace: colorspace, colors: [
+			CGColor(red: 1, green: 0x00p-8, blue: 0, alpha: 1),
+			CGColor(red: 1, green: 0xaap-8, blue: 0, alpha: 1)
+		] as CFArray, locations: [0, 1])!,
+		start: CGPointMake(0, 100), end: CGPointMake(0, size.height - 100),
+		options: CGGradientDrawingOptions(rawValue: 0))
+	context.restoreGState()
+
+	context.move(to: CGPoint(x: size.width * 0.30, y: size.height * 0.30))
+	context.addLine(to: CGPoint(x: size.width * 0.30, y: size.height * 0.70))
+	context.addLine(to: CGPoint(x: size.width * 0.575, y: size.height * 0.425))
+	context.move(to: CGPoint(x: size.width * 0.70, y: size.height * 0.30))
+	context.addLine(to: CGPoint(x: size.width * 0.70, y: size.height * 0.70))
+	context.addLine(to: CGPoint(x: size.width * 0.425, y: size.height * 0.425))
+	context.setLineWidth(80)
+	context.setLineCap(.round)
+	context.setLineJoin(.round)
+	context.setStrokeColor(CGColor.white)
+	context.strokePath()
+	return context.makeImage()
+}
+
+if CommandLine.arguments.count != 2 {
+	print("Usage: \(CommandLine.arguments.first!) OUTPUT.icns")
+	exit(EXIT_FAILURE)
+}
+
+let filename = CommandLine.arguments[1]
+
+let macOSSizes: Array<CGFloat> = [16, 32, 128, 256, 512]
+let icns = CGImageDestinationCreateWithURL(
+	URL(fileURLWithPath: filename) as CFURL,
+	UTType.icns.identifier as CFString, macOSSizes.count * 2, nil)!
+for size in macOSSizes {
+	CGImageDestinationAddImage(icns, drawIcon(scale: size / 1024.0)!, nil)
+	CGImageDestinationAddImage(icns, drawIcon(scale: size / 1024.0 * 2)!, [
+			kCGImagePropertyDPIWidth: 144,
+			kCGImagePropertyDPIHeight: 144,
+		] as CFDictionary)
+}
+if !CGImageDestinationFinalize(icns) {
+	print("ICNS finalization failed.")
+	exit(EXIT_FAILURE)
+}